Residential energy savings through modified control of space-conditioning equipment

Energy requirements for heating and cooling homes depend strongly on how the space conditioning equipment is operated. Using detailed computer simulations for a typical house, the energy savings for decreasing winter thermostat settings and for further reductions during the night are given as a function of climate. Similarly, the energy savings for increased thermostat settings during the air-conditioning season are given for the coterminous states. Air-conditioning requirements can also be reduced by allowing natural ventilation to cool homes under certain outdoor conditions. A comparison between air-conditioning only and a combination of air-conditioning and opening windows is given for the coterminous states. Energy savings for all of these options are highly dependent upon local climates. Total savings from adoption of these behavioral changes are equivalent to one-fourth of U.S. imported petroleum.     

Estimating energy savings due to conservation programmes: The BPA residential weatherization pilot programme

The Bonneville Power Administration operated a residential weatherization pilot programme from 1980 to 1982. The programme provided free home energy audits to more than 7000 electrically heated homes in the Pacific Northwest and gave zero-interest loans to weatherize over 4000 of these homes. The total cost of the programme was $11 million. This paper describes several mehtods used to estimate the net energy-saving effect of the BPA programme (ie the electricity saving that could be directly attributed to the programme). The simplest method ivolves estimation of weather adjusted annual electricity consumption for each household. The second approach uses this weather adjusted consumption as the dependent variable in a pooled time-series cross-section regression model of electricity use. The third approach involves estimation of qualitative choice models of the decisions to retrofit and to participate in the BPA programme. Results from these models are used to define Mills ratio terms that are then used as explanatory variables in the regression model of the second approach. The range in estimated programme saving, given the diversity of analytical methods used, is surprisingly small — 3100–3300 kWh/year per average programme participant.     

The unrecognized contribution of renewable energy to Europe's energy savings target

We show that renewable energy contributes to Europe's 2020 primary energy savings target. This contribution, which is to a large extent still unknown and not recognized by policy makers, results from the way renewable energy is dealt with in Europe's energy statistics. We discuss the policy consequences and argue that the ‘energy savings’ occurring from the accounting of renewable energy should not distract attention from demand-side energy savings in sectors such as transport, industry and the built environment. The consequence of such a distraction could be that many of the benefits from demand-side energy savings, for example lower energy bills, increase of the renewable energy share in energy consumption without investing in new renewable capacity, and long-term climate targets to reduce greenhouse gas emissions by more than 80%, will be missed. Such distraction is not hypothetical since Europe's 2020 renewable energy target is binding whereas the 2020 primary energy savings target is only indicative.     

Evaluation of methods used to determine realized energy savings

Most methods to determine realized total energy savings at national or sectoral level make choices, or neglect problems, which hamper the calculation of sound and useful energy-saving figures. Issues are the choice of the right aggregation level, the appropriate variables to construct a reference energy consumption trend, the energy quantities to be applied and interaction between various effects. Uncertainty margins for results lack in most presentations as well. This paper presents six methods, illustrates the adverse effects of certain choices and problems, and investigates how these methods deal with them. The methods are scored with respect to the issues mentioned above. Finally, a number of improvements are suggested, among which the use of final energy demand expressed in primary energy units, and bottom-up analyses at the level of real saving options. The last option is the more important, as it could provide top-down evaluation results (total savings from decomposition) as well as bottom-up policy monitoring results, both being crucial to new European energy-saving policy.     

Rewarding energy savings rather than energy efficiency: Exploring the concept of a feed-in tariff for energy savings

Financial incentives are important for overcoming certain market barriers to improved energy efficiency and for the adoption of energy efficient technologies. Financial incentives are mainly focused on the introduction of specific technologies, rather than behavioural change. While the declared goal of financial support schemes very often is to save energy or reduce harmful emissions rather than to foster new technologies per se, it is often encountered that such financial support for energy efficient technologies may not ensure real energy savings due to the rebound effect and various market barriers.In the area of renewable energies it is common for financial support to be given to power producers for the verified production of renewable electricity, in the form of a guaranteed financial incentive (feed-in tariff). In the energy efficiency policy research little attention has been paid to the possible use of a “feed-in tariff” in the form of a financial incentive based on the kWh saved by the end-user. This paper discusses the possible setup of a feed-in tariff designed to reward energy savings.     

An intelligent system for the climate control and energy savings in agricultural greenhouses

A greenhouse for crop production is a complex thermodynamic system where the indoor temperature and the humidity conditions have a great impact on the crop yields. This system can be considered a multivariable input output system MIMO. This paper aims at presenting a physical model of a greenhouse, experimentally validated, in order to propose a fuzzy-based controller to manage the indoor climate of a greenhouse using some actuators (induction motors, heating system etc.…) for ventilation, heating, humidifying, and dehumidifying purposes. In addition, a novel approach is presented for energy management by involving the photovoltaic energy in order to minimize the use of conventional electrical grid and to lower costs of agriculture production. The photovoltaic (PV) generator will serve to power a direct torque control (DTC) controlled induction motor which drive a variable speed fan. The validation of the physical model shows a high agreement with the experimental measurement. The simulation results show the effectiveness of the fuzzy controller as well as the PV generator for saving the energy and lowering the costs of crop production into greenhouses.     

Assessment of energy savings from the revised building energy code of Thailand

The government of Thailand legislated an Energy Conservation Promotion Act (ECP Act) in 1992 and set bye-laws that identify designated buildings (DBs) and detail mandatory requirements for energy conservation for DBs in 1995. An Energy Conservation Promotion Fund (ENCON Fund) was also created to fund energy audits on 1900 DBs. Recently the requirements and procedures for energy conservation in buildings have been revised where system performance requirements for building envelope, lighting, air-conditioning, and hot water generation are adopted. Moreover, the new building energy code (BEC) distinguishes different categories of DBs, provides credit for use of solar energy, and introduces a new option of whole building energy compliance. The authors develop building models from data obtained from energy audit reports and use them to estimate savings on energy and peak demand from future new buildings using forecasted energy and peak demand data from the Load Forecast Subcommittee, a panel tasked to forecast future electric load of Thailand. From a modest level of energy saving in the first year that the code is expected to be enforced, the level of saving rise to over 10% and 20% annually of requirement of target buildings in 6 and 12 years respectively.     

Quantifying the savings of an industry energy efficiency programme

In a developed economy, improving the energy performance of the industry sector can make an important contribution to achieving national energy efficiency goals. Policy measures aimed at increasing energy efficiency in industry must be proven to be effective. In Ireland one such measure is the Large Industry Energy Network (LIEN) programme. LIEN is a voluntary network of large energy users, facilitated by the national energy agency, working to maintain strong energy management practices. In this paper, we combine top-down methods for analysing national energy statistics with company-level figures supplied by LIEN participants to quantify the energy savings achieved by the companies and to determine the fraction of national savings that can be attributed to them. By comparing the collective performance of participant companies with the performance of the rest of industry we provide an indication of the effectiveness of the programme and quantify the savings that may be directly attributable to it. These figures when combined with national energy forecasts for industry help us assess the likely contribution of the programme to future national energy savings targets.     

A statistical approach to the determination of energy savings in a solar-assisted water-heating system

A method of determining the cost benefits of a flat-plate solar-energy collector system used for domestic hot-water preheat is reported. Because the method obviates the need for a non-solar heated control comparison and does not call for any temperature logging within the system it is ideally suited to existing installations. The method relies on a statistical analysis of readily-available data and has been applied to assess the savings made in a number of flats within an Edinburgh tenement block. Several different combinations of data inputs may be used with varying degrees of reliability in the results.     

Prospects of energy savings in the national meat processing factory

This investigation is conducted to examine potential opportunities of energy savings in the meat processing industry. It demonstrates that energy saving can be considered as a major factor to increase profit and competition within this sector. Detailed energy audits were carried out for meat processing equipment in the national factory. This work shows that there are large opportunities of savings which can be achieved by installing the economiser; using compressed air leakage points in the distribution air network, increasing the suction temperature of the high stage compressors as well as recovering of heat in blow down by preheating feed water which will save even more energy. It was found that the refrigeration systems consume more electricity compared to other departments. However, modification of the water pumping system will save an extra amount of energy. Finally, valuable recommendations to factory management are proposed and required additional research, analysis, and data collection are identified.     

Household water conservation: The role of indirect energy savings

Recent regulations specify a cost-effectiveness analysis of implementing household water conservation measures to reduce the flow of wastewater as a prerequisite to federal funding of wastewater treatment plant construction. There is a wide variety of devices available to conserve water: hot water as well as water at ambient temperature. In this analysis we use a sample of 23 metropolitan areas to evaluate the indirect household energy savings which results from conservation devices to save hot water.

Devices to conserve hot water are cost-effective in all 23 metropolitan areas up to an equivalent annual cost of $1.50/1000 gal saved under an assumption of no inflation in energy prices, and about $7.00/1000 gal saved under an assumption of 20%/yr inflation in energy prices. The impact of the indirect energy savings can be further illustrated by noting that devices to conserve ambient temperature water are cost-ineffective in all 23 metropolitan areas at equivalent annual costs above $1.00/1000 gal saved. Besides increasing the level of cost-effective household water conservation from 114 gal/day to 146 gal/day for a family of four, while providing significant economic savings, the indirect energy savings from hot-water conservation devices can provide a 46–62% reduction in energy use for residential water heating.     

Air pollutants due to energy supply in Mexico

The impacts on the air of the net internal supply is studied at national level. Energy balances were modified to directly link emissions with energy usage. A relation was selected between each Joule used and kilogram of pollution emitted, for each primary energy source and main contaminant. The evolution during the last two decades of emissions due to energy supply was obtained; as well as the relation to the energies' own evolution.     

Optimizing energy savings of the injection molding process by using a cloud energy management system

The injection molding (IM) process is a widely used manufacturing process for injecting material into a mold for producing a diverse array of parts. It includes several energy-consuming procedures, such as heating plastic pellets, forcing melted polymer into a mold cavity, and cooling down the molded products. In this study, developmental factors of IM machines and processes along with energy savings progress are reviewed. In addition to several machining factors and process parameter optimizations, applying an energy management system (EMS), as well as new tools to reduce energy consumption in the IM process, has the potential for great improvements in the long term. A cloud energy management system (CEMS), called the intelligent Energy Management Network (iEN), which was launched by Chunghwa Telecom, was installed on two IM machines to illustrate the optimization of energy savings by a variable-frequency drive (VFD) and process parameter optimization. Through the recorded process dynamics, the energy usage, and product quality of the IM process using the iEN, the energy savings could be analyzed by the expert, measurement and verification (M&V) systems on the software as a service (SaaS) platform. The electricity savings on the IM machine after installing a VFD were 41.3%. Further optimization by using the one-factor-at-a-time (OFAT) approach to measure the process parameters, such as melting temperature (310.0~350.0 °C), mold temperature (110.0~130.0 °C), and clamping force (120.0~160.0 T), was carried out. The experimental and analyzed results indicated that the optimal operating conditions were at a melting temperature of 330.0 °C, a mold temperature of 120.0 °C, and a clamping force of 140.0 T. Through the optimization procedure of the process parameters carried out by the iEN, further electricity savings of 12.2% were added. Therefore, the saved electricity cost and payback period of installing the VFD and the iEN were NT$ 26,363/month and within 4 months, respectively. The saved electricity and reduced carbon dioxide (CO₂) amounts were 107,200.5 kWh/year and 55,851.5 kg/year, respectively. Continuous analysis of the optimization process, energy savings, resource conservation, and waste reduction of the IM process using the iEN has shown overall benefits to the IM process, the machines, and the future decisions and designs regarding new products.     

The novel use of phase change materials in refrigeration plant. Part 3: PCM for control and energy savings

Phase change materials (PCMs) have been recognized as energy storage tanks since the 1980s. The ‘tank’ has been introduced into the refrigeration system to enable its capacitance to take account of fluctuations in the daily cooling load. However, this part of the paper will present a novel control purpose of using PCM in refrigeration systems. The novel application of PCMs in refrigeration systems at different positions in the refrigeration cycle circuit with a shell and tube structure has been investigated extensively by the novel mathematical model presented in part 2 of the paper. The results show that for energy savings, PCMs at different positions give coefficient of performances (COPs) up to 8% through lowering the sub-cooling. PCMs also improve the system COPs up to 4% and 7% for the thermostatic expansion valve (TEV) and orifice systems, respectively, by minimizing the superheat. Further benefits such as system stabilization were also observed in this investigation.     

Passive building energy savings: A review of building envelope components

A significant portion of the total primary energy is consumed by today's buildings in developed countries. In many of these buildings, the energy consumption can be significantly reduced by adopting energy efficiency strategies. Due to environmental concerns and the high cost of energy in recent years there has been a renewed interest in building energy efficiency. This article strives to make an exhaustive technical review of the building envelope components and respective improvements from an energy efficiency perspective. Different types of energy efficient walls such as Trombe walls, ventilated walls, and glazed walls are discussed. Performance of different fenestration technologies including aerogel, vacuum glazing and frames are presented. Advances in energy efficient roofs including the contemporary green roofs, photovoltaic roofs, radiant-transmittive barrier and evaporative roof cooling systems are discussed. Various types of thermal insulation materials are enumerated along with selection criteria of these materials. The effects of thermal mass and phase change material on building cooling/heating loads and peak loads are discussed. Application of thermal mass as an energy saving method is more effective in places where the outside ambient air temperature differences between the days and nights are high. Air tightness and infiltration of building envelopes are discussed as they play a crucial role in the energy consumption of a building. Energy efficiency approaches sometimes might not require additional capital investment. For example, a holistic energy efficient building design approach can reduce the size of mechanical systems compensating the additional cost of energy efficiency features.     

新能源汽车的发展现状与对策

一直以来,中国及世界上的大部分国家都受化石燃料等不可再生能源所带来的环境问题和可持续发展问题所困扰.阐述了世界能源日渐匮乏的现状和各国采取的应对措施.汽车消耗了全球汽油的40%,其排放的尾气占大气污染源总量的50%以上.随着资源与环境双重压力的增大,发展新能源汽车势在必行.浅议了汽车尾气产生的环境污染和治理方法,总结了部分国家和地区新能源汽车的发展现状和政策法规.旨在普及新能源汽车知识,使人们对其产生深刻印象,加大新能源汽车的推广力度.     

Potential energy savings by application of the novel CRIMSON aluminium casting process

Compared with its output the casting industry uses a disproportionate amount of energy as a result of the inefficient processes used. This paper presents the melting processes that are used in one of the traditional foundries and identifies the energy burdens associated with them. A comparison is then made with the new CRIMSON process to demonstrate where energy savings can be made. An actual case or casting sample is investigated to demonstrate the advantage of energy saving in CRIMSON method which will help the foundry industry in reduction of energy cost and promote competitiveness in the production of high end casting components.     

折标系数的选取及其对节能量核算的影响

针对企业节能量核算过程中折标系数的选取问题,以实际案例为基础,通过对可采取的各种方法进行比较分析,提出较为快捷准确的折标系数计算方法,并进一步探讨了折标系数选取对节能量核算的影响,以供节能量核查机构和企业能源部门参考。     

Heat Roadmap Europe: Combining district heating with heat savings to decarbonise the EU energy system

Six different strategies have recently been proposed for the European Union (EU) energy system in the European Commission's report, Energy Roadmap 2050. The objective for these strategies is to identify how the EU can reach its target of an 80% reduction in annual greenhouse gas emissions in 2050 compared to 1990 levels. None of these scenarios involve the large-scale implementation of district heating, but instead they focus on the electrification of the heating sector (primarily using heat pumps) and/or the large-scale implementation of electricity and heat savings. In this paper, the potential for district heating in the EU between now and 2050 is identified, based on extensive and detailed mapping of the EU heat demand and various supply options. Subsequently, a new ‘district heating plus heat savings’ scenario is technically and economically assessed from an energy systems perspective. The results indicate that with district heating, the EU energy system will be able to achieve the same reductions in primary energy supply and carbon dioxide emissions as the existing alternatives proposed. However, with district heating these goals can be achieved at a lower cost, with heating and cooling costs reduced by approximately 15%.